1. Field of the Invention
The present invention relates to an information retrieval device, an information retrieval method, and a program to be executed by a computer.
2. Description of Related Art
Using search to obtain information from Web pages and blogs has been becoming common practice (see Japanese Unexamined Patent Application Publication No. 2004-287827). In such search, users create a search expression by using AND, OR, and NOT conditions. Then, when referring to original texts hit in the search, if no information to be retrieved is displayed, they modify the search expression.
In such search, it is difficult to retrieve only web pages having contents that the users are seeking after. In particular, search results often include unrelated articles. For example, when search is performed with a term “note”, a lot of articles that do not belong to the category of “note” that the user desires, such as stationery notebooks, names of cars (Note), titles of movies/cartoons (XX's note) and the likes, are also retrieved.
To perform search while preventing these plurality of topics from being mixed together, users may create a search expression using AND, OR, and NOT conditions in their own. However, it is very difficult for users to create such a search expression unless they have technical knowledge and are adept at searching (herein after referred to as “experts”).
Furthermore, even if they are experts, a satisfactory search expression still cannot be created unless they repeat “try-and-error” during which actual searches are performed with various search expressions, original texts are perused, and search expressions are re-created and so forth.
The present invention has been made to solve problems existing in the above-described techniques, and an exemplary object of the invention is to provide an information retrieval device, an information retrieval method, and a program to be executed by a computer, which can relieve the load on the user when creating formula for information retrieval.